The present invention relates to an air conditioning apparatus for an automotive vehicle. An apparatus of the present type is disclosed in U.S. Pat. No. 3,263,739 which constitutes the closest known prior art.
Generally, the apparatus comprises a duct in which is provided a heater core and an air conditioner evaporator. The outlet of the duct leads into a passenger compartment of the vehicle. The inlet of the duct may be connected to the atmosphere or to the passenger compartment for recirculation. Movable dampers are provided in the duct to control the temperature and connect the inlet and outlet of the duct is required by the mode of operation.
The temperature in the passenger compartment, duct and the like is sensed and the dampers positioned to automatically maintain the temperature at a desired value. This is accomplished by modulating vacuum from a suitable source and applying the modulated vacuum to vacuum motors or actuators which position the dampers in accordance with the level of vacuum.
Although the basic apparatus is generally satisfactory and advantageous, the system is prone to failure of a sensor, control unit or the like. Under such conditions, the hot air may be blown into the passenger compartment in the summer and cold air blown into the passenger compartment in the winter through the duct. This makes the temperature in the passenger compartment extremely uncomfortable and interferes with the driver's ability to safely operate the vehicle. Although the apparatus may be shut off, this results no air conditioning whatsoever and the temperature in the passenger compartment will approach the temperature of the atmosphere. This results in only a smaller degree of discomfort.